SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52dff58d6a66179b4a1b14837df89ac75ff40f72a0477bdf8aac20d02d69cf0d' 
  AND token = 'eOfuYyU0yj2JuSuxZNfn+JaPIMLbGPndNQ1rHsEaUqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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