SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83aabc3ffc7db51ecccf182e431a4c8c266fb1368b77f763878e0275d7fb4e17' 
  AND token = 'Jr37pTFwH00YdAZLTEK+ZdNsJP8iIakzAlNZR7J3Bvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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