SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5433567af7a757c2e7aff1846618be8c396674f7dc664829e18a77a184bab1' 
  AND token = '9I4M21zaD2WD/1MS8T2XOUKGku2PWDHh4n4/76j6OaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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