SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb21350ef6e80fce3b03ea33b38b4d4d3668e54004c3bae932a6851937772a96' 
  AND token = 'hCskxL4FluK284CQjwpTP9ufY9UKXNWM7tZLbp3WiNs=' 
  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"
    }
  }
}