SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fd5f09b2de1608f4b7485778cded91b362c6a6936bb80278522743f552b3baa' 
  AND token = 'oP3ZKcWkGhcJJrO/Pc7+ae7YwlA4vTVPtNK2r/sG9+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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