SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9868c0996eacdadbe6e44ce98207d4b71d089fbcfe88098f855a8bf60a2f7d16' 
  AND token = 'xNtSo4LS/eGa7hsjUIuZ8xQYuyJ+M9OmjIgjwk5tc08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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