SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '181eaf52a5b3694294bd69d76e9c3f412b8edbd147b238d9b0da5a1313c2dde3' 
  AND token = 'J1w7YkLNUhjQgHVb5wM2tcx7DMiB08e8I2+OSn8BRFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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