SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a38d9d9a8fbb18b2a1798bd46cdca047abd35ef4fe139f3a36f30c7970f3b4c0' 
  AND token = 'xNxctFm05epn/G3ITEMoSm8smwS7LiQSHddwORJiwyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}