SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '147b1ff532c919edc831ab589834a014c149087776c67bc1c58eb7acecf1d471' 
  AND token = 'dsLQgTSoxIdOUCLEHtrdf9zoS+GhWacquztxxX+0hEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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