SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83db2ccb81b6c05ab23249615c7d9894267049e82ec982dfd9245f94a68a6e4' 
  AND token = 'MM1RWrXB8YpBmidOLaPiVl79DVMI0sd3hliOb4TtP8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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