SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c853c6120b17e022daff0b5c3dc51bcaf27c7852a6cbc46a3b4dfe696688928' 
  AND token = 'p3wsW+6CaLJcHkjBXCAvkHFUsVm1/+wD0Wm7GvGNV28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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