SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ded919f69b3f962f4d97f8ea7572210b4616eaed4c62b57fccc9e7ab5dd008ff' 
  AND token = '2mAZJ6CmULAAEyS5MwPf9VfQP9x+qenAL8Kle9Y4sGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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