SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542f0e23994df646d2222edff0e24b73bef8dc7af8ed307173e1163f774488f8' 
  AND token = 'FKYQDKnZPk40XnvUQG2uR7eiMPKSnViWG7JNS6Xe1VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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