SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c7649c48201b0f70e1cedbada07bc792b4fbfcfc8d5e56fd61005b70608ed0a0' 
  AND token = 't3YughiQoVuP/zDGgxXSpFKp3geAVn8AJB48Ud5KUIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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