SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d1b84382849e8ede3901a4f9926898ac95e609ec2c978462e0dbd6c0667a7f' 
  AND token = 'N2S/wwFwAwNMr0cy1Ee1iClpqKziXhIpbP8e/dWYpqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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