SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18c4983cdb8067265d28b576727cecf58d236879fa0f23b858ff5cf903d8cba3' 
  AND token = 'vsTDsTRrP/Nu1JYU9YwRW/glSL9lFAnXKrnDG9Dscio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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