SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d239c2dd12a2ca533f943436f5e48951dc29975010871d6b963dd031a92e01b' 
  AND token = '8aCG+alJC7pdHbwEpM+UQ3EayHtZPPDtt46JK9HDl8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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