SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8e56bf9ec1936f0c1ec2edfb4bf6860258c92736a90c1f97222da0d22020702' 
  AND token = '48ciAkorkycmCGgO3O+z0BlgfhuatgSfbGZk7lEJF6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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