SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e1b847bead3b3d7899ab24cc1d22ff5862818c64c7fb88558dea8db4fd5b07b' 
  AND token = 'eKYs9p+yTnvmElly8GJwDoYbzNzQrXaevyiwXec0szA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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