SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b6991efacf41ebde92df2b0adf024c5693c29c19bfff7fb6aac5e4e0ba55bee' 
  AND token = 'TT/JjlfqPazDcubIk+O+8Kyq6nxN7bTj6iVAKNzDBGg=' 
  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"
    }
  }
}