SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a17c1c53f0dc683e9c969e1262a0dff6e119a6e15aab2e681d2871b49bdd09' 
  AND token = 'cs/wHnejia0kG6nMigKf0hkemEAdlAjI5F80B8FNRc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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