SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da493db7f0949ca85a0845e60a901bdcf5a540c39c7e0fd72a1183ee2a3d14b5' 
  AND token = 'iswgDh3MVwqDX5zmLmH/URPnxXM6loJKehYIEgwq3m8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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