SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '680ec44de9e11d014c509ef6b1b264f1b157ac36528a913528117c206c803b18' 
  AND token = 'P9Vq+Q2WC5FIKaElfMT17rKre/1AAlmFKWfmbnpJO9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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