SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1fede973632d7fb322f445a9c7960e14247c0ecc528072e857bba245840372' 
  AND token = 'VHHwNQqm8Diz1iMO8Q6s8eYNZn+oQUxH1ghMLzx5quY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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