SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08233b7951c4da22dd80a80adf5e1f33cd6f86b025d80a41b7d959b31c0099ea' 
  AND token = 'AQOOP3qGkFe9GLiwsTKzhbNXZjRly6lHJo/Dpgkgruw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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