SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dbe42e1b9a9213805a9b3f2c700b2e17c27375d14b56f86b0cb39bf9c6290553' 
  AND token = 'PqRDTxi5erBxGZzLwcLfGpqGzZVXkIW5cdi59UrYjIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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