SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b326ad2386d8cc403acf97d9e964cb309a1fb03afd49f9a0e9f4f0001c53966' 
  AND token = 'tZCtJjTUIr1D0lhdsQlH1gaAXgccT0n6u/6sqCJcGuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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