SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a950a585583fb60b0afe859b5769f8d863389846e8c89230d5506e67d8b30132' 
  AND token = 'nmJR0a/87f+YU4hB1FbifCnYn/eQtW7DwRBJmyHDIRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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