SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96ede84ec1ba581a39daaadf05348535e26f77c21a5b54a82dab4fc35cbc0968' 
  AND token = 'cDs5AfeaMvNJBARkH0SILWwXKgNgGkwi9JvUWRURNO8=' 
  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"
    }
  }
}