SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c785c91b106f51fda5fec27058197ed7632a635b94bfdf84646bdec6995e3a' 
  AND token = 'JlfszDuHSCGA/dvEZ+iPUjmj556EOrRwqEy4nCfEnh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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