SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '236a4653dca725b5d6a10e6f6dfb14c75367f4c7412e732b0782248be9d71537' 
  AND token = 'uzw1o/rxS6ingPFYJ+8FRpcJNs3mGWa+WxIBxkpcGjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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