SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '143fa68be55ea69207037a0f5af679fdf04508c762b0b017f4d358ed08ccae07' 
  AND token = 'LTlGUdLkgZJJAXFlPc8SytHeVCboG1Gh2jBVFDkaJMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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