SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d589f7497cef97c5d68b8ed6a8b9d3258a4735635fe58b5ce5d26b46ee1662f' 
  AND token = 'dHLBO1ePgcQLYA3WA4YWdJa1M4sHMfwiA23WYBUaRiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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