SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675247e373fe82e38ee9065ce6fdf2a6d61f198dbb2681563177c9ea4e12a0fa' 
  AND token = 'oVh+VgmN3aKPrGoQgxrJF9pXBJiZwAhpAyrXjWeB+7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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