SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780dbfffd8993f87187a03059e14ec311388cde103be2b6c11fdce1a48b98fb7' 
  AND token = 'oncdPt+WsjAZBVeliJxwc6zSeZK+o0u/ib4gJImlH4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}