SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fd0b5d21f73f6b447839dcfdcbb2bb9b60a033643967e631fe9f92b3101da74' 
  AND token = 'vVK9BhZmwTGYsW1YXzC52F3ErUnJTaIbmN5zsAaOvXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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