SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c6903633ac0534fd0b0d0c6de5ccb84f02623292ea6e1bdb88d172ca74898ad' 
  AND token = 'seSYHJfgQ3vcp4rxuna0ZWoUTZRGOv7WVOVLmcjlgHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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