SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ffb8cf765eaf16db79650483af1b235740e9269199ba809092f6d6d3f1b376e' 
  AND token = 'pGXEgbXdygbgLdqgGQ+mw6Xpn/G+xSHX2Tn4mFK0z/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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