SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c83ff9efe5363d4190d33987ba54192d0ad3fb791ae32db9c0327ec9fdc34491' 
  AND token = 'AOd7BdO72/MXW9Tt+A8kHaTZQNaBBdFizNo+BUoKZiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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