SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '044eb31410b7398b4155ea8f87a1baca267fd128b11b66b448f5f7562e06e9ef' 
  AND token = '4AamGfFJ/sxw/G/dH49nXGNLZUejoWfessU/tvduorA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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