SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dca3d9ef55f85dbed8500b506c5487c37d73aeb4c818c31149a40e06e830829' 
  AND token = 'drtkAlOwZra5g7PVThOTr9yVlJdGn8Q6Qhcq/K/MKLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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