SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebc088b4f444410b0f374b93dd1de2857164e1ccfbc993b4b70a47dbc313ad0b' 
  AND token = 'kiTU6oeiORi/1Lxh+iFk/kEYOQStmbKxlNEF5kejnF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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