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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f83cc6bcf3eac01fe16543db2fad56c90b65b9bcbe5bf9a4694843e33ba2e02f' 
  AND token = 'MQg79Wwdxk7/wz/wBwoh7VLzTg1B0Df31LgZVnMXUUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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