SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b47e18c2fe52f2fb622c59990d19c4b0699187b965a9dd6d12346aedecdea11' 
  AND token = 'NMveoNz/vF0ClfHfq9bbT2A0oNDdenOvKMwPdN7eC5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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