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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c42ba2036fc0adc9da599ce0df962152ba386756be02bd2b3d8809d7dce9db' 
  AND token = 'Zg9TMVgJ32qbXEst0rWK6aXmB7VvQf4Hw6WxqgcjcAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}