SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e300462d3adcf6306680a58b3f46970e5e1776c254aba32286cc70fb6cafbd2f' 
  AND token = 'w/cnKIXHPzQRu3kUofXhqWXP4VEJAvXbHwc9u15KQVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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