SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fcbf23a4a9c21d965903f75a09c3c060774dd35d13e4a6ca88f48bff539bef5' 
  AND token = 'i6plvYIibpkzbT53Zr6OX6cjw3rPn2avI85zbWQGXGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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