SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07674ca2f1a674e83c4b31c3d6f93821b53b75b0cbe80c5a51b65e9a5d233a67' 
  AND token = 'r/DEENNJsZqQJOPHjKESJ+5gHoVzIdxRA9SvHh/1Dt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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