SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd332c9d69e305b9fdee066e5544118736b279135e3dbf04a3aa8188b8ece6a5a' 
  AND token = '8fJYWW6Ja8b7mB6DVD2/2ehKBvFkgWq24TM0ovp27j0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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