SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e3393fe84ea59c2bcb813edc7c000118cc82b33ea6e81f8d08f94e51be4040f' 
  AND token = 'jkoiKyAgqo92LmUZTU6EU8OGctgTofnkjz1SaH+GgMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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