SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fff2398bac337aba659ec7330ec57dc4dec82e23cfa7a0463c13c24fd46437f' 
  AND token = '3Okd8b6bm2yjXXJ0oPsiqLxiHlWufvFF8W8LRLzKnn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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