SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56d434fc4704a07a98b1a058ff9aab079d783868da9af36a64ed2efaf1f773e4' 
  AND token = '5yGFV0WdkjlWRf3gvjocPVUoKE1mKAYaxq77nTBPIOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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