SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a44e1b7f6f3131131a345ed154014577c5da4d7d9218187713925ff3daa8687' 
  AND token = 'Da928xYIf9qQig0yaF6Ke2+PHHOAGA+Vi3H4OjbPU/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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