SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7484bf3a9dc19436776c3d13d261110b4976bf208fc81adcf4595096feee42e0' 
  AND token = '+TqjtKSkl5BUIRuvZaRaYWXnxGmDGIvxXb9KYyIi/lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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