SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a12a8e4ac2dc88ba760538e7ee8c66be286c4bc44b81dab758e3a20e52770d0' 
  AND token = 'o8+HOWcct5vSqp1OzkN2NfrNdMVL9OHS+FTaC7XPcN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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