SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d27e544fdd81bc23acd84415a90eeec982951fc6166bd73809ed72da379a9b' 
  AND token = 'CPPn7madqjdWbVx5M3kdBoaXZ+tVbkq7rXdx+CbJzas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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