SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb4e271a5b83de05302311f349d13784e2b1a34007c69dec1df9da2296c25441' 
  AND token = 'WWqO4opFcH88jwELYrc7NEHwGxldU3RFU+bJ1wE+cBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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