SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cdc7a0b84a462bee9fc3e9341989d90885629463568faee1a87f63261b153a10' 
  AND token = 'xNZWx3z5N8gGnhSpv1VzVI6M/mu5Zy6l/fhkadBDXng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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