SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '270e47a9dfec1373ddf343989a2c862e4a3569cb70f3b9ac9f6bdc7af646f419' 
  AND token = '9TpfIgOGPoDT3Octk+3BvjbDIJDNQL93UBFq3yvlN0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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