SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92810c23ebeabc53665646803d9889f51b342092bed94527fd254a165f530bd' 
  AND token = 'dhEzy9HFVcK83OorHIW9FmRuQCQwNtj/9HIFfH3l2eQ=' 
  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"
    }
  }
}