SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39f490b71aed52e28733b97c7545350fb244b5ca66317903358fb7d10b9305ce' 
  AND token = 'pk4eUsJDNTcW2gOLlhsT3srQpV5HeKmZsFiJQn5cI4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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