SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5751457f4f79350b71fceebce7014e98d43b85153ac8ce744c12fec022158e0d' 
  AND token = 'oIR2k4iH13biUIZIK8ide/M3r6PzBOhcu+NkZ2YR9wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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