SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85bd52f191b9d29bdb98b3862f075d2262224ed878cc3afcb4990d5af850e6b8' 
  AND token = 'SGNAaregHpfXtaXFkiS7JcP3NSIjbxH3js7qGKRAtD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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