SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8b31775d8ea4903c36ee53b69ee8420087decb640980c535cd75a8cdb1d066' 
  AND token = 'xadvHDWl2qXUoBolx5nltuc1UZezoi8VS8DeciRWeTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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