SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd392b71b16f70de88b5fb4ac3f198875e2e8b6214b905457b4fb97a5692c2889' 
  AND token = 'S9oioEiAPmloxe0fBp9iteXfsDcmahm9em+1dd55ZEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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