SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8ffbf1e5a5273d7a3106292d93ce970056a601ab938159bab605d732192a3f4' 
  AND token = 'eSR5yKURDFIYHnPpy7WLKZmw3umaStmpgxnNWyrf8d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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