SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8de2de4e4cdf6377ebe5e6794fbb7957ab6ef6e46f02b5982553278707fc3591' 
  AND token = 'Er+SfRWJTKvXer1PoiaOQO6arCxBrN6aooQvQxtXp98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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