SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af6aff6c39bf2864ff47357db73c53c8da092fc2ae222bae2f13d88b651bb7f7' 
  AND token = 'PnanPy+CeYn6b2qSJQxetbpVKge1axUnAb80cTx8+4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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