SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '186692a7ca391440721cadc3fd941a82d8448804bb22a64d5f4a8b6a0ebcf817' 
  AND token = 'VuJSc18BNV+T7cl/WwFKkrBzqfLfKJTIhFhx3UvBBS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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