SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cc7c3d8b505eb0014cc6b715f8408d59ae119625504c2e644676f995564b367' 
  AND token = '9GkMzOcrpu3gL60kgAgi3KSyFAaTWShnxWJu4O+PWkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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