SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56339b0ee5d1b3f458f732e15a93b71b8529419ee7d0322714b89a35e2011209' 
  AND token = 'PIC8rS2avOhjdc1Tx/XcajumJ1A5+4qMS4FNqJeBiuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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