SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24f977c7c580487cfd6ff90bcdf60874f769f114303687f1a520f2d57b2252ae' 
  AND token = 'oXgmsItprwIuzpwHhCour9IaJH58rqLQ0Y4z3vgwIAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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