SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fd89f460394dbfc57907c28c2323793f4bbf6dc4307c3731a2293930df29d1e' 
  AND token = 'KMrkUNzk1DCl2fggQjMWpiLol/2DjdPm3spCkrYkAho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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