SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd527dd2779796faf1419d5450925082a3c3096afbb47e3c75126dc3aec7c5a28' 
  AND token = 'r6jG9rAP3BfUv+kpLkV9ZZaTsy+2S/BqQ4XcdSMUuWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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