SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '548f92e67057575d3ec9c3ac1ea436c803fa9afe6b0eac89c78a1e684916da6a' 
  AND token = '+lVRrW55HeucYlkPs8UGeUKGVpgFIodfsd/2dWpdUzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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