SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e2c94eb2a82d874a03f06215be0bd7db8c2e2b125c95fdc88370c71f774d263' 
  AND token = 'X3lkPvpCnRHnzlV76uk6/aDCSaIfp3eXWR+7w3F2rKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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