SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a95b54df971ba7c407464b4391206ab2e317e7680a28edbbde7a25cf3583fe47' 
  AND token = 'ygF1xEkknDTmNVWrfYbaMH0dMeaupAYYYkvu3ZQ+LFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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