SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c4954917927a33afd3af7a6087aeb837e40e6ed3a7817130bfe50dd05e1d244' 
  AND token = 'f9xqz60Q1CxO0sBIDBF3uDhI/mOiglZg4z35PIEMBtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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