SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4941a1ebf058bced91d3f1c4b6441a64a57d7e7496d7a604fe1a85ea045f10' 
  AND token = 'TvRmqd9VdYIjbdtRDLYfAlcce2vI+azqnqn6/Nlvuds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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