SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991297df0a8ee41f22cd240cfc955748dcba4e9d8af8008c7b12b5477787cf2c' 
  AND token = 'Yz7JKnD4X0lLliU8VvOsKxa4cTz78p5Xc64cdlkRHmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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