SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7857d2ad52bfeb7caa71c0b240506830ca1e4bdcbdd72a4d69bb577cb223774' 
  AND token = 'XfCDL/dxowNWPiE1pIzFq4AniEO1nr9j2E1UjhcgEXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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