SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81a24eeb75863362f26cecac52789d193e28ddf4008df87c366be07988cb191f' 
  AND token = '5KmYma+2Vxrf+7/BC9UNF8ymn5X/K3ZOmhl218dIjh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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