SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b57e26dfeb8089f2f5e973457f27f937d4e1895e0a51874522f3332ec3186b7' 
  AND token = 'aHZhEPaEs2PPQ2Sds+Pp34NWIjFhYoJGjXmbWJlFKVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}