SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90bfde9bd313a9e160e71699ef1cd025bb3b353cb204cf89cb7e68978abd6e15' 
  AND token = 'nnbaIrro5IUE+wXR0n7pOEUp5muipxa+cj2iMR0HGvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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