SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82a744d3bd15660d4a005ede1139601eb0a22942fbba60e11dabf9cbb4f023f6' 
  AND token = 'zleZbvrqRy9o/C0ZnS5sZd5jGsZJMWk3y60vW8LMQvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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