SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b8ebf8c4f8148e2f237ba546c296e2c0072ce40611fd3a45b66ab3aa754082c' 
  AND token = 'hRYCcGVXgEMCnXBT6PZ3sAs5vvuosEUI4UDdLGtfNNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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