SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbe1b65cd6b83b7ec70d280f707250c0b36e2c3739aaaf1426bf6fb1a9f82198' 
  AND token = 'ZWubMgb/hLr8lkYqd5rmmatsHWWV4NRDPFcN/tZqwpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}