SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f3642759d658431b706b2e229f568fc0979396931647150827318db4b128004' 
  AND token = '8xRVTxCQY34Su/Hvu+B+de6lp3PMFEwiG295gzV3SKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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