SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a55c32d6c5aaa32400de1acbb8c66b9e291790dd59f061e8687bfaace5a2406' 
  AND token = 'Fxrntvyb1qrX/oKSPhlnFWvZvxBkhZd48gqG3TuSLO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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