SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '403387d510b6cccaa47cc9b9028216213fb9294ca8944d461917f6d8ec79bab2' 
  AND token = 'qKAh5dtcDqmTocCtc6ZRUpzuwJtfPs/Bknkgj8G1y+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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