SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1872cfe8e6bbdb08e0c7c9deb7376cd791de13a373776251baa5864d9a893e17' 
  AND token = 'FX42MGe/uroQQaoopXrKJzLqGAIsoR+dBNzrn5TnYec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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