SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ab01688bbc3b7ff7e71b08b38fa8a778046a6b0d4b7e7841404b3fee5949b77' 
  AND token = 'msUC/UwJ5IQGyUhA/xLnKAvmfnca+ePfducuezFQroY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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