SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c8b118aff8fed6dacc814417c55c370e66b5e7a3a09c82561a75de528dfef5' 
  AND token = '/do4QJ+UdKZmmqMLsTAxseN+qF78JqgDofi4okd/2po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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