SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a4ad162b459d56f35f9b4c152563a2febc8e47ec426371d8a790e0fd37a422a3' 
  AND token = 'yeqc1iaOh6rFnzb4OH2oTA4wC3tadPmR1n71lmzeU2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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