SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d9c96f03d1c544b5a50a79c32073a0875caf612040b0143198534d2bd813d2' 
  AND token = 'JInOltQpfE19jN09wKEaRhgfW0A3YpRa9buzIYqj1vs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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