SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39b00c45e13529c079a7c3b2c5c9f1cc848bf3dfde711528f4f85d8bbd0a650d' 
  AND token = 'gKv80DgQK+IHPozZFDnmMZMpRL7BRo8jw5JpEpFpLNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00095

JSON explain

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