SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c826f8639cbca758b0ed7fccdddfe20cea54937eb191f877a7cf4ad2636e454a' 
  AND token = '72ZO0NE7mqiG05kBYh2ZQkpwXXL3zd1Gw2HqF93uJYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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