SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '679566d10ce257b70922bf112af8538855076ab4cc72d5b21ec890f3da9c48bf' 
  AND token = 'ewp/bld9+0WnHQ8gJmshPgmjB6Nz8A7fasSt1vo7rKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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