SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a643ba609abafbb573fe36055a9971faa67c394587e90baa256781f085234a1' 
  AND token = 'THcLmhU4GfxaZpST1rYHANbxqtTDvwg6XkJKvDjAd7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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