SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d62f44e76c40ed20e346dc63b21412bce663cab2e06789b60f42ec236a0dce5' 
  AND token = 'gkxVNchw0uu3zGmdtQatzMTDEuPVxWrlNm79gECA7PM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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