SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '390f50b7ae1f424ab6d4b75d5742cfba347e947ca01acb7c112f1f106dd7dfb8' 
  AND token = '285nq0xPX3QCHZBwfwO1eCDz7WbUOchd1Bzp2ns475s=' 
  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"
    }
  }
}