SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '537ed59eb4c139be0fff0aa37ab208dbd69809f448e7d10cb97b23750dd20f1b' 
  AND token = 'lrjF9UuSvI0DPYTJuUItpLqnkGH+Rjsf/K+yIgY276g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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