SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f58584c07fb412eef97e8c17116c016de323d7ea63d0967a65a766f265a76aa' 
  AND token = 'Cv9lGPxBqs8z/Hh9+Mhsc9x7VZ+bjMpQTdSeueKin2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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