SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4fc6375d2436bb3d2ace14980bfaf96cb38b851f44cadcb91d5a40f039149f6' 
  AND token = 'vCFTmf33/drI/kCzMcG1sTVsNNjNGUU5S+qP3k0V0ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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