SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36112120366fdf38f4f2a74929987693256e5ec083365aa6c29bd959797a304f' 
  AND token = 'BNFjR24doaWJ65ZuNwStypHvZzV8tU7tOmhEvTX1rQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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