SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28feb08b683c01bc0ab209f37d4880641f293558c8ed7d076392bc9383adbb8' 
  AND token = 'EhgRuznFIsiQgQ5awXQlqgWIr/PyVauPqvv19qQmz1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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