SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f66d8adbcd95e3d72764974ea92a3ce5edaa5ecd66bd281c14bbaa68eeb7f621' 
  AND token = 'BpAxfhSsURnoQhgjUoeEURpSFAhMNnTCNVK7YM8LZdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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