SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecf55a2920e36a54a7fc8b13ba25e95d8f562c3f07aad83cb53d3198e07f8d5' 
  AND token = 'YAXVaVJ9fhGw2UACJUNe9MnKqSl1d5baaW8Klr/BHko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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